Surface mount pointing device having signal conditioning components

ABSTRACT

A pointing stick for controlling cursor movement on a display screen of a computer system that is mountable to a surface of a printed circuit board. The pointing stick has a base member and a shaft having mounted in the base member. Several sensors are mounted around the shaft for sensing the amount of strain in the shaft that is created in response to an applied force on the shaft. The sensors generate an electrical signal in response to the applied force. A pair of spaced electrical leads are located on opposing sides of the base member and extend partially through the base member. Each of the electrical leads has several inner terminal ends that are electrically connected to the sensors. Several outer terminal ends extend outwardly of the base member and are shaped for mounting on the surface of a circuit board. An electronic component is attached to the shaft or the leads and is electrically connected to the inner terminal ends. The electronic component receives the electrical signal from the sensors as an input and generates a conditioned electrical signal as an output.

CROSS REFERENCE TO CO-PENDING AND RELATED APPLICATIONS

This invention is a continuation in part of U.S. patent application Ser.No. 09/258,513 filed on Feb. 25, 1999, entitled “Integrated SurfaceMount Pointing Device”, having a common assignee and a common inventorand is herein incorporated by reference in its entirety.

This application is related to the following applications which areherein incorporated by reference in their entirety for supportive andrelated teachings:

U.S. patent application Ser. No. 09/168,022, filed Oct. 7, 1998, titled“Pointing Stick Having Chip Resistors”.

U.S. patent application Ser. No. 09/149,966, filed Sep. 9, 1998 is apointing stick having integral control circuitry and has the sameassignee as the present invention.

U.S. patent application Ser. No. 08/717,517, filed Sep. 23, 1996, nowU.S. Pat. No. 5,894,301 is a collar mounted pointing stick and has thesame assignee as the present invention.

U.S. patent application Ser. No. 08/938,274, filed Sep. 26, 1997 is aunified bodied z-axis pointing stick and has the same assignee as thepresent invention.

U.S. patent application Ser. No. 08/794,703, filed Feb. 4, 1997 is az-axis pointing stick with ESD protection and has the same assignee asthe present invention.

U.S. patent application Ser. No. 09/082,700, filed May 21, 1997 is apointing stick having an interposer connecting layer and has the sameassignee as the present invention.

U.S. patent application Ser. No. 09/149,713, filed Sep. 9, 1998, nowU.S. Pat. No. 6,002,388 is a pointing stick having a flexible interposerand has the same assignee as the present invention.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to a pointing device for controllingthe positioning, movement and operation of a cursor on a display screenassociated with a computer and, more particularly, to an integratedpointing device that is mountable to a printed circuit board.

2. Description of the Related Art

Various devices are well known for controlling cursor movement over adisplay screen associated with a computer. Depending on the type ofcomputer program in operation, the position of the cursor on a displayscreen may indicate a choice of computer commands on a menu associatedwith the computer program displayed on the display screen menu. One suchdevice is a “mouse” which has a ball mounted to its underside forcontacting a horizontal surface and rolling therealong when manipulatedby a computer operator. The X- and Y-axis components of movement aresensed and transmitted through a connecting cable to a serial input portof the computer. This signal to the computer is varied by the amount anddirection of mouse ball movement, and causes a corresponding movement ofthe cursor on the display screen. Typically a pair of “mouse” or “click”buttons are located on the top of the mouse at the forward end thereof.The buttons permit a computer operator to enter a selection or othercommand to the computer (the command typically being shown by theposition of the cursor on the displayed menu) upon pressing one or theother or both buttons, depending upon the software associated with themouse. Such a device, which is separate from the computer console andkeyboard, requires a connection to a computer port and a flat,horizontal supporting surface for proper operation. Furthermore, thecomputer operator must completely remove one hand from the computerkeyboard in order to move the mouse and thus the cursor on the displayscreen and then reposition the hand again over the keys of the keyboardto resume data entry.

Another cursor controlling and signaling mechanism is a “joystick”which, like the mouse, is completely separated from the computer consoleand keyboard. The joystick is typically an elongated, upright stick thatextends upwardly from a base connected to the computer console by meansof an electrical cable. The joystick is operated by tilting the uprightstick in various directions to cause the cursor or other display elementto move on the display screen in a direction and usually at a speedcorresponding to the direction and pressure exerted on the stick by thecomputer operator. The operation of a joystick, however, frequentlyrequires that both hands be moved from the computer keyboard, with onehand holding the base and the other hand manipulating the joystick. A“click” button is usually located on the joystick. Although a mouse orjoystick can be used with a portable “laptop” or “notebook” sizedcomputer, such devices are cumbersome, since they must be carriedseparately and connected to the computer before use. Moreover, suchdevices are not suitable for operation during travel.

A “trackball” is still another type of known cursor controlling device.This device, which in essence is an inverted mouse, includes a rotatableball mounted within a housing. The ball is rotated by a finger, thumb orpalm of the computer operator, and the X- and Y-components of movementare sensed and input into the computer with corresponding movement ofthe cursor across the display screen. “Mouse” or “click” buttons areusually located on the trackball housing, although with some models aselection signal is input by pressing the “enter” key on the standardkeyboard. This type of pointing device has been somewhat useful withportable computers because it can be temporarily affixed to one side ofthe computer case for manipulation by one hand of the computer operator.However, although trackball devices can be removably mounted to thecomputer case, they still required attachment before use and removalafter use and repositioning of the computer operator's hand during use.It is also noted that some trackball's are built into the computerkeyboard. Nonetheless, these trackball's required a separate set of“click” buttons for selection of items on the display monitor.

Manufacturers of portable laptop computers, recognizing the need forplacing the cursor controlling device in a permanent and more convenientlocation, have more recently installed a small, stubby button-likejoystick at a central position on the computer keyboard, such as at thejuncture of the “g,” “h” and “b” keys of the standard “QWERTY” keyboard.The button-like joystick, also known as a pointing stick, is sensitiveto lateral pressure, the amount and direction of which are sensed andinput into the computer to cause movement of the cursor, with the speedand direction of cursor movement corresponding to the amount anddirection of pressure on the pointing stick. In order to select items onthe display screen, upwardly extending “mouse” or “click” buttons mustbe provided somewhere on the computer, typically at a location remotefrom the pointing stick. This, as with the previously described cursorcontrol devices, is disadvantageous since the hand and fingers of thecomputer operator must be repositioned in order to actuate the buttonsand then be moved again to the proper keyboard position for typing.

Another disadvantage associated with a keyboard-mounted pointing stickis that a communication cable must extend from the pointing stick to acircuit board that provides a power source, amplifiers, and calibrationelectronics for the pointing stick. The circuit board is spaced from thepointing stick and care must be exercised when installing the cabletherebetween. Moreover, the materials that make up the cable, itsprocess of forming and method of attachment to the pointing stickcontribute to increased overall cost of the pointing stick.

Examples of patents related to the present invention are as follows,wherein each patent is herein incorporated by reference for related andsupporting teachings:

U.S. Patent No. Re. 5,956,018 discloses a compact pointing control stickcircuit board assembly having electrical vias.

The foregoing patents reflect the state of the art of which theapplicant is aware and are tendered with the view toward dischargingapplicants' acknowledged duty of candor in disclosing information thatmay be pertinent in the examination of this application. It is expresslystipulated, however, that none of these patents teach or render obvious,singly or when considered in combination, applicants' claimed invention.

SUMMARY OF THE INVENTION

It is a feature of the present invention to provide a pointing stick forcontrolling cursor movement on a display screen of a computer system.

It is a further feature of the present invention to provide an pointingstick device for controlling cursor movement on a display screen of acomputer system that is mountable to a surface of a circuit board.

Another feature of the present invention is to provide a surface-mountpointing device for controlling the movement of an object on a displayscreen that includes a base member and a shaft having a first end and asecond end. The first end mounted in the base member. Several sensorsare mounted around the shaft for sensing the amount of strain in theshaft that is created in response to an applied force on the shaft in atleast a first direction. The sensors generate an electrical signal inresponse to the applied force. A pair of spaced electrical leads arelocated on opposing sides of the base member and extend at leastpartially through the base member. Each of the electrical leads hasseveral inner terminal ends that are electrically connected to at leastone of the sensors. Several outer terminal ends extend outwardly of thebase member and are shaped for mounting on the surface of a circuitboard. One or more electronic components are attached to the first endof the shaft and are electrically connected to one of the inner terminalends. The electronic component receives the electrical signal from thesensors as an input and generates a conditioned electrical signal as anoutput.

There has thus been outlined the more important features of theinvention so that the detailed description thereof that follows may bebetter understood, and so that the present contribution to the art maybe better appreciated. There are, of course, additional features of theinvention that will be described hereinafter which will form the subjectmatter of the appended claims. Those skilled in the art will appreciatethat the preferred embodiment may readily be used as of basis fordesigning other structures, methods and systems for carrying out theseveral purposes of the present invention. It is important, therefore,that the claims are regarded as including such equivalent constructionssince they do not depart from the spirit and scope of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of an integrated surface-mount pointingdevice according to a first embodiment of the invention;

FIG. 2 is a top plan view of the integrated pointing device of FIG. 1;

FIG. 3 is an isometric view of the integrated pointing device mounted ona computer keyboard;

FIG. 4 is a cross sectional plan view of the integrated pointing deviceof FIG. 1 with the pointing stick removed for clarity;

FIG. 5 is an enlarged cross sectional view within the dashed circle ofFIG. 4;

FIG. 6 is a cross sectional elevation view of the integrated pointingdevice of FIG. 1;

FIG. 7 is an electrical schematic of a bridge circuit incorporating thestrain sensitive elements of the integrated pointing device;

FIG. 8 is an isometric view of an integrated surface-mount pointingdevice according to a second embodiment of the invention; and

FIG. 9 is a cross sectional plan view of the integrated pointing stickof FIG. 8.

FIG. 10 is a side cross-sectional view of a surface mount pointing stickhaving a control circuit mounted on the package.

FIG. 11 is a bottom view of FIG. 10 with part of the housing removed toshow the control circuitry mounted.

FIG. 12 is a side view of the surface-mount pointing stick.

It is noted that the drawings of the invention may not necessarily be toscale. The drawings are merely schematic representations, not intendedto portray specific parameters of the invention. The drawings areintended to depict only typical embodiments of the invention, andtherefore should not be considered as limiting the scope of theinvention. The invention will be described with additional specificityand detail through the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference now to the drawings, and to FIGS. 1 and 2 in particular,an integrated surface-mount pointing device 10 that can be used tocontrol the movement of a cursor on a computer screen (not shown) isillustrated. In particular, the pointing device 10 comprises an uprightpointing stick or shaft 12, strain gauge sensors 14 located on the sides20 of the stick 12, outer terminals 16 electrically connected with thestrain gauge sensors 14, and a body 18 for supporting the stick 12 andthe outer terminals 16.

As shown in FIG. 3, the pointing device 10 is surface-mounted on aprinted circuit board 21 using well-known techniques. The circuit board21 is in turn installed in a typing keyboard having a plurality of keys,such as keys 22, 24 and 26 (shown in phantom line) representative ofletters, numerals, and/or symbols. Preferably, the keyboard is of thestandard “QWERTY” type and the circuit board is mounted in the keyboardat a location such that the pointing stick 12 is positioned at thejuncture between the “G” key 22, the “H” key 24, and the “B” key 26.Although this is the preferred location for the stick 12, it is to beunderstood that the pointing device 10 can be mounted at otherlocations, either on or off the keyboard. A resilient cap 28 (shown inphantom line), which may be formed of rubber-like material, ispositioned over the top of stick 12 to increase the ease of operatingthe stick. The cap is sized to receive a single finger of an operatorfor controlling cursor movement on a computer screen in response topressure exerted against the cap (and consequently the stick 12) in adesired cursor direction. The finger pressure causes strain in the stick12 that is sensed by the strain gauges 14.

Referring again to FIGS. 1 and 2, the pointing stick 12 may beconstructed of electrically insulative material, such as alumina orother ceramic. In the embodiment illustrated, the stick 12 issubstantially square in cross section and formed with four side surfaces20 for receiving the strain gauges 14. Although alumina is the preferredmaterial for the pointing stick 12, it is contemplated that othersuitable materials, such as plastics, epoxy resin, metals, or the like,can be used.

With additional reference to FIGS. 4 and 5, the outer terminals 16 areformed in pairs on a lead 30. Each lead 30 comprises one pair of outerterminals 16 and an inner terminal 32 connected by a middle section 34.Each of the inner terminals preferably extends into an opening 46 in thebody 18, but can terminate at the edge of the opening or proximalthereto. Preferably, eight leads 30 are arranged around a central axisof the body 18, with a pair 38 of leads 30 arranged on each side 36 ofthe body 18 such that four outer terminals 16 project outwardly anddownwardly from each side. The leads 30 in each lead pair 38 arepreferably mirror images of each other. Arrangement of the leads 30 inthis fashion offers several advantages. Since only the outer terminals16 are in contact with the printed circuit board (PCB), the number ofouter terminals 16 is related to the holding strength of the device 10on the PCB 21. A larger number of outer terminals permits the use ofsmaller and thinner leads and increased holding strength than if fewerterminals are used. Consequently, greater resistance to separation ofthe pointing device 10 from the PCB 21 is realized, especially duringoperation of the pointing stick 12 where forces may be generated in theX, Y and Z axes, or any combination thereof. The symmetrical orientationof the outer terminals 16 contributes to symmetrical loading along theseaxes when the pointing stick 12 is operated and facilitates alignment ofthe pointing device 10 with the printed circuit board during themounting operation. With the use of smaller and thinner leads, the outerterminals 16 can be formed with a relatively small bending radius tothereby form a relatively small footprint for the pointing device 10.The leads may initially be pre-formed in their proper orientation aspart of a lead frame (not shown) for facilitating automatic assembly ofthe integrated pointing device 10. Although four outer terminals 16 areshown on each side 36 of the body 18, more or less outer terminals maybe formed, depending on the number of strain gauges 14, the amount ofholding strength desired, and so on.

The outer terminals 16 of the leads 30 are shown in FIG. 1 with agull-wing shape, but may be formed into any shape so as to be attachableto a printed circuit board, including, but not limited to J-lead,thru-hole and butt terminal shapes.

With reference now to FIG. 6, the body 18 comprises a base 40 and acollar 42 integrally formed with the base, although the collar may beformed separately and attached to the base through suitable adhesives,ultrasonic welding, or other well known bonding techniques. The base 40is preferably generally square-shaped with four sides 36 and includes acavity 44 formed in the base. The body 18 is preferably constructed ofplastic material and the base 40 is molded around the middle section 34of the leads 30 during an insert-molding process. Alternatively, thebase 40 may be constructed of separate plastic sheet material bondedtogether with the leads 30 sandwiched therebetween. An opening 46extends through the collar 42 and base 40 and is in communication withthe cavity 44. The pointing stick 12 extends through the opening 46 in aZ-axis direction 48, and is held in place by a suitable adhesivematerial 49, such as a cyanoacrylate adhesive epoxy material. Theparticular adhesive used should be compatible with the materials of thepointing stick 12 and body 18.

The strain gauges 14 are mounted on the sides 20 of the stick 12. Eachstrain gauge comprises spaced pressure sensitive strips 50 that extendgenerally parallel to each other in the Z-axis direction 48, aconductive contact bridge 52 extending between the strips 50 at theirupper end for electrically connecting the two strips 50, and aconductive contact pad 54 electrically connected to a lower end of eachstrip 50. Preferably, the conductive contact pads 54 are formed as lowerextensions of the pressure sensitive strips 50.

The pressure sensitive strips 50 are formed of a material that exhibitsa change in electrical properties, such as resistance, in response tothe amount of strain applied thereto. Preferably, a resistive thick filmmaterial is screen printed onto the sides 20 of the pointing stick 12.Alternatively, a resistive thin film material can be sputtered onto thesides 20. The conductive bridge 52 and pad 54 are also adhered to thesides 20 in a well-known or similar manner.

With reference to FIGS. 5 and 6, leads 30 of a lead pair 38 areelectrically connected to opposite ends of one of the strain gauges 14(represented as R1, R2, R3 and R4 in FIG. 5) at their inner terminals32, wherein a connected pair of strips 50 represents a single straingauge 14. Each contact pad 54 is bonded to an aligned inner terminal 32by any suitable bond material 50, such as tin-lead solder. In thismanner, the outer terminals 16 are electrically connected to the straingauges 14.

Since there are four outer terminals 16 associated with each straingauge 14 in this embodiment, the printed circuit board 21 is formed withelectrical traces that interconnect selected pairs of outer terminals16. For example, as shown in FIGS. 4 and 5, traces 60 to 70 electricallyconnect one end of strain gauges R1 and R3 to a positive voltage source,while traces 72 to 82 electrically connect one end of strain gauges R2and R4 to ground. Likewise, traces 84 and 86 connect the opposite end ofstrain gauge R3 to indicate strain in the positive X-axis direction;traces 88 and 90 connect the opposite end of strain gauge R1 to indicatestrain in the positive Y-axis direction; traces 92 and 94 connect theopposite end of strain gauge R4 to indicate strain in the negativeX-axis direction; and traces 96 and 98 connect the opposite end ofstrain gauge R2 to indicate strain in the negative Y-axis direction.

Referring now to FIG. 7, an electrical schematic 100 of a bridge circuitincorporating the strain gauges 14 is shown. Specifically, this circuitis an example of how the Z-axis pointing stick can be arranged tointerface with the electronics (not shown) on the circuit board 21. Thestrain gauges 14 on opposing sides of the stick 12 are configured in twohalf bridge circuits, resistors R1 (Y+) and R2 (Y−) form a first halfbridge, while resistors R3 (X+) and R4 (X−) form the second half bridge.A fixed resistor 102 is connected between the supply voltage 104 of thesystem and a node 106. The X OUT output 108, Y OUT output 110, and Z OUToutput 112 are amplified by three differential amplifiers 114, 116, and118, respectively. Each amplifier has a variable reference voltageinput. These reference voltages are calibrated to set the output to zeroalong each axis when no force is applied to the stick 12. The X and Yaxis outputs 116 and 118 are developed when an X or Y directional forceis applied to the stick 12. For example, when a force is applied in theX direction, the X− and X+ strain sensitive resistors change resistancein opposite directions and cause an output change. The same is true forthe Y-axis. A Z-axis output is developed when a Z-axis force is appliedto the top of the stick 12. Force in the Z-axis causes all strain gaugeresistors 14 on the stick 12 to change in a negative direction. Thischange lowers the total impedance of the two half bridges. The lowerbridge impedance causes a voltage change in the Z OUT output 112 sincethe series resistor 102 is fixed.

With reference now to FIGS. 8 and 9, an integrated surface-mountedpointing device 200 according to a further embodiment of the inventionis illustrated, wherein like parts in the previous embodiment arerepresented by like numerals. As in the previous embodiment, thepointing device 200 comprises an upright pointing stick or shaft 12,strain gauges 14 located on the sides 20 of the stick 12, and a body 18with a collar 42 and base 44. A total of six leads 202 to 212 are moldedinto the base 44. Each of the leads 202, 204, 208 and 210 comprises anouter terminal 16 and an inner terminal 32 separated by a middle section34, while the leads 206 and 212 comprises an outer terminal 16 and apair of inner terminals 32. Each of the inner terminals preferablyextends into the opening 46 in the body 18, but can terminate at theedge of the opening or proximal thereto. Three leads 202, 204 and 206are arranged on one side of the body 18, while the remaining leads 208,210 and 212 are arranged on the opposite side of the body 18.

The connection of the leads to the strain gauges 14 is similar to thatshown in FIG. 5, with the exception that the lead 212 is connectedbetween a positive voltage source and one end of strain gauges R1 and R3through its pair of inner terminals 32, and the lead 206 is connectedbetween ground and one end of strain gauges R2 and R4 through its pairof inner terminals 32. Likewise, the lead 210 is connected to theopposite end of strain gauge R3 to indicate strain in the positiveX-axis direction; the lead 202 is connected to the opposite end ofstrain gauge R1 to indicate strain in the positive Y-axis direction; thelead 204 is connected to the opposite end of strain gauge R4 to indicatestrain in the negative X-axis direction; and the lead 208 is connectedto the opposite end of strain gauge R2 to indicate strain in thenegative Y-axis direction. With this arrangement, the separate traces onthe circuit board of the previous embodiment, as schematicallyrepresented in FIG. 4, can be eliminated. The electrical schematic asshown in FIG. 7 can remain the same for this embodiment.

Referring to FIGS. 10 and 11, a surface-mount pointing stick havingsignal conditioning circuitry assembly 300 according to a furtherembodiment of the invention is illustrated, wherein like parts in theprevious embodiment are represented by like numerals. As in the previousembodiment, the pointing stick 300 comprises an upright pointing stickor shaft 12, strain gauges 14 located on the sides 20 of the stick 12with resistors 50 and contact pads 54. Stick 12 has an upper end 12A anda lower end 12B. A soft cap 302 covers stick 12. A plastic molded base40 is located around shaft 12. A total of eight gull wing shaped outermetal leads 310 are molded into the base 40. Each of the leads 310 hasan outer terminal 16 and an inner terminal 32 connected by a middlesection 34. Outer terminals 16 are adapted to mount to a surface mountprinted circuit board. A total of eight inner leads 312 are also moldedinto base 40. Inner leads 312 are short and are contained within base40. Inner leads 312 has an curved end 312C, a middle part 312B and abond pad end 312A. Curved end 312C curves up into contact with pad 54and is attached to pad 54 by a solder joint 56. Solder joint 56 makesand electrical connection between pad 54 and lead 312. Four of outerleads 310 are arranged on one side of the base 40, while the remainingfour outer leads 310 are arranged on the opposite side of the base 40.Inner leads 312 are placed two on each side of stick 12.

A conventional semiconductor die attach adhesive 350 is used to attachan integrated circuit semiconductor chip or die 352 to the lower end 12Bof stick 12. The die 352 may also overlap with the adhesive 350 onto thebottom side of middle part 312B. A conventional ultrasonic gold oraluminum wire bond 354 is used to electrically attach wire bond pad 358on die 352 to bond pad end 312A. Integrated circuit 352 contains signalconditioning circuitry that is able to accept an analog signalindicative of force and direction from the resistors 50 as an input andprovide as an output a conditioned electrical signal. Such a conditionedsignal could be an amplified signal and one that is converted into adigital format by an analog to digital converter. An integrated circuitperforming such functions is available from Philips corporation and iscalled Trackpoint. The input signal is provided to die 352 by leads 312and the output signal is placed on some of leads 310. Power and groundvoltages would also be supplied to integrated circuit 352 by some ofleads 310.

Surface-mount pointing stick having signal conditioning circuitry 300 isassembled in the following manner: The eight leads 310 and 312 arecontained or held together by a lead frame (not shown) that isfabricated in a continuous reel by stamping or chemical etching. Thestick 12 is placed into leads 312 and between curved ends 312C anddipped into molten solder form solder joint 56. Next, the die adhesive350 is dispensed onto stick bottom 12B and die 352 is place ontoadhesive 350. Adhesive 350 is then cured. A conventional wirebondmachine applies an ultrasonic gold or aluminum wire bond 354 between pad358 and inner terminal end pad 312A or inner terminal 32. The lead frameis removed from the reel. Next, base 40 is molded over die 352, leads310, 312 and the lower half of stick 12. The leads are formed into agull wing shape after the molding process. Last, cap 302 is applied overstick 12. If desired assembly 300 can be tested.

Referring to FIG. 12, a surface-mount pointing stick having signalconditioning circuitry assembly 400 according to a further embodiment ofthe invention is illustrated, wherein like parts in the previousembodiment are represented by like numerals. FIG. 12 is identical toFIG. 10, except that adhesive 350 is only attached to inner leads 312and is not attached to shaft end 12B. The die 352 is connected to leads312 by adhesive 350.

Remarks About the Preferred Embodiments

One of ordinary skill in the arts of strain gages and ceramic materials,and more particularly the art of designing pointing sticks with straingages on the sides, will realize many advantages from using thepreferred embodiment. In particular, strain gages are devices that sensethe amount and direction of applied pressure placed upon the pointingstick. The sensed pressure creates electrical output signals used todirect the cursor on a display device. Thus, the side-mounted straingages enables control of both the direction of cursor movement and theselection of items on the display device by tapping the pointing sticklike the clicking of a mouse button. Of course, a skilled artisan willrealize that the body 18 may have some flexure in a downward directionduring the application of tapping force, especially with the cavity 44arranged around the stick. Specifically, the flexing of the body 18around the cavity will cause some force to be applied to the sensor fromthe top portion of the walls of the opening 46. However, the stick andsensor design can equally work without a cavity or flexure of the baseside walls by simply sensing the strain created in the stick 12.

It will be noted that the collar 42 shifts the region of highest strainfrom the base 44 to the top of the collar 42 so that the maximum straincoincides with the resistor strips 50. With this arrangement, the entirelength of the stick can be shortened. Specifically, when the stick 12 isshortened, there is a decrease in the amount of strain generated alongthe stick 12 when a person pushes the pointing stick with the finger.With the addition of the collar 42, the strain gauges 14 are now capableof sensing enough strain to be able to generate detectable andunderstandable electrical signals representative of the applied strain.

It is further noted that a skilled artisan would realize that thepointing device 10 is now capable of performing selection and draggingof icons on a monitor in addition to double clicking for selection of anitem. In this operation, the user would hold down the pointing stick 12while exerting additional force in the X-Y plane for controlling thedirection of the icon being dragged. All of these functions are nowcapable of being performed with a single finger while the remainingfingers are located on the keyboard.

It can be seen that the embodiments of FIGS. 10 and 11, assembly 300allow the signal conditioning circuitry to be mounted close to theresistors minimizing any coupled noise that may be introduced in thesystem and reducing shielding requirements. Further, the assembly 300,packages the signal processing circuitry into a more compact packagethan had been done previously.

The above-described embodiments can be constructed with the samedimensions and lead pitches as standard commercially available ICpackages. The compact size would allow for its use in a wide variety ofapplications, while the minimal parts and ease of assembly of theabove-described embodiments also renders the device relativelyinexpensive to produce.

Variations of the Preferred Embodiment(s)

One of ordinary skill in the art of making pointing devices will realizethat there are many different ways of accomplishing the preferredembodiment. For example, although the bonding compound 49 is illustratedbetween the body 18 and the stick 12, it may not be required when theopening 46 is sized to fit securely around the stick 12.

Even though the embodiments are discussed in conjunction with the use ofstrain gages on all four sides of the stick 12, it is contemplated thatonly two sides of the stick 12 can be used for sensing only either thepositive or negative strain on the bending of the stick for creating theresulting control signals.

It is to be understood that the X, Y, and Z axes, as well as the termsupper, lower, etc., and their respective derivatives as used herein areintended to describe relative, rather than absolute directions and/orpositions.

While the invention has been taught with specific reference to theseembodiments, someone skilled in the art will recognize that changes canbe made in form and detail without departing from the spirit and thescope of the invention. The describe embodiments are to be considered inall respects only as illustrative and not restrictive. The scope of theinvention is, therefore, indicated by the appended claims rather than bythe foregoing description. All changes that come within the meaning andrange of equivalency of the claims are to be embraced within theirscope.

What is claimed is:
 1. A surface-mount pointing device for controllingthe movement of an object on a display screen, comprising: a) a basemember; b) a shaft having a first end and a second end, with the firstend mounted in the base member; c) a plurality of sensors, mountedaround the shaft for sensing the amount of strain in the shaft that iscreated in response to an applied force on the shaft in at least a firstdirection, the sensors generating an electrical signal in response tothe applied force; d) a pair of spaced electrical leads disposed onopposing sides of the base member and extending at least partiallythrough the base member, each electrical lead having a plurality ofinner terminal ends electrically connected to at least one of thesensors, and a plurality of outer terminal ends extending outwardly ofthe base member and being shaped for mounting on the surface of acircuit board; and e) at least one electronic component, attached to thefirst end of the shaft and electrically connected to at least one of theinner terminal ends, the electronic component operable to receive theelectrical signal from the sensors as an input and generate aconditioned electrical signal as an output.
 2. The surface-mountpointing device according to claim 1, wherein the electronic componentis attached to the first end of the shaft with an adhesive.
 3. Thesurface-mount pointing device according to claim 2, wherein theelectronic component is electrically connected to the inner terminal endby a wire bond extending from the inner terminal end to a wire bond pad.4. The surface-mount pointing device according to claim 3, wherein theelectronic component is enclosed within the base member.
 5. Thesurface-mount pointing device according to claim 4, wherein the shape ofthe outer terminal ends is selected from the group consisting of:a)gull-wing; b) J-lead; or c) butt terminal.
 6. The surface-mountpointing device according to claim 5, wherein a cap is located over thesecond end of the shaft.
 7. The surface-mount pointing device accordingto claim 1, wherein the electronic component is attached to one of theelectrical leads with an adhesive.
 8. The surface-mount pointing deviceaccording to claim 1, wherein the electronic component is attached toone of the electrical leads with solder.
 9. The surface-mount pointingdevice according to claim 2, wherein the electronic component iselectrically connected to the inner terminal end by a solder joint.